Employee Benefit Plans (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020 USD ($) plan	Jun. 29, 2019 USD ($)	Jun. 27, 2020 USD ($) plan	Jun. 29, 2019 USD ($)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Amount Company expects to contribute to its pension plans	$ 4,800		$ 4,800
Payment for pension benefits			$ 2,400	$ 1,500
Defined Benefit Plan, Additional Information [Abstract]
Number Of Multiemployer Plans, Withdrawal Obligation Could Be Material | plan	2		2
Number Of Multiemployer Plans Withdrawal Obligation Could Be Material Certified Red Zone | plan	1		1
Number of Multiemployer Plans, Certified Red Zone | plan	5		5
Number of Multiemployer Plans, Certified Yellow Zone | plan	2		2
Number Of Multiemployer Plans, Withdrawal Obligation | plan	5		5
Accrued liability representing the present value of scheduled withdrawal liability payments for under-funded multi-employer plan	$ 2,800		$ 2,800
Multiemployer Plans, Withdrawal Obligation, Settlement	2,500
Maximum [Member]
Defined Benefit Plan, Additional Information [Abstract]
Multiemployer Plan, Contributions To Individual Plan, Percent			5.00%
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	749	$ 683	$ 1,504	1,361
Interest cost	1,430	1,714	2,858	3,424
Expected return on plan assets	(2,032)	(1,817)	(4,071)	(3,636)
Amortization of prior service cost	8	9	16	18
Amortization of net loss	854	1,147	1,708	2,293
Net pension cost	$ 1,009	$ 1,736	$ 2,015	$ 3,460